January 05, 2010
OCTO Publishes New, Enhanced Detailed District Topography Data
Topographic map lines, record the District’s local detail in intervals of two feet—a significant improvement in clarity and detail over the previous 1995 District topography data, which recorded detail in much larger intervals of one meter.
New two foot interval contours provide significant improvement in clarity and detail over the previous 1995 District topography data, recorded at one meter intervals.
Today OCTO’s DC GIS group announced the release of the long awaited 2009 Topography for the District of Columbia. The new data is now available for download from the OCTO data download site, data.octo.dc.gov.
The 2009 Topography measures the District’s elevations and slopes using both line and point representations. Topographic map lines, also known as contours, record the District’s local detail in intervals of two feet—a significant improvement in clarity and detail over the previous 1995 District topography data, which recorded detail in much larger intervals of one meter. The new data includes not only two-foot-interval contour lines, but also specific spot elevation points and break lines for real-life features such as bodies of water, road edges, railroad tracks, bridges and paved parking areas.
Planners, developers, and environmentalists throughout the metropolitan area will benefit from the new topographic data, which will help them add precision to the planning and implementation of all types of construction projects. Consideration of the District’s topographic features, both natural and man-made, is important to reduce construction costs, minimize risks from natural hazards like flooding, and minimize the environmental impacts of proposed development.
“The District and Federal governments are investing millions of dollars to protect against flooding in the center of our city, and accurate elevation information is essential to doing it right,” said Harriet Tregoning, Director of the District’s Office of Planning. “We’re delighted that DC GIS continues to help provide the information we need for an increasingly accurate picture of the city in which we live.”
“I’m very pleased to offer new and improved District topographic data to the planning and development community and the general public,” said District Chief Technology Officer Bryan Sivak. “This richer, more powerful data reflects the continuous enhancement that has made the District a national leader in GIS.”
The 2009 topography datasets meet the USGS National Map Accuracy Standards (NMAS) for 1:1200 scale mapping and the American Society for Photogrammetric and Remote Sensing (ASPRS) Class 1.5 Accuracy Standard. For additional information on topography data accuracy and specifications, please read the supporting topographic documentation or email email@example.com.